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3 years ago

Can someone please help me

Physics

1 answer:

mario62 [17]3 years ago

8 0

Answer:

GE = ME - $\frac{1}{2} m\,v^2$ , which agrees with option C in your list.

Explanation:

The definition of Mechanical Energy (ME) of a system is the addition of the gravitational potential energy (GE) plus the kinetic energy (KE) of the system:

ME = GE + KE

Given that the KE is: $\frac{1}{2} m\,v^2$ ,

solving for GE in the formula above gives:

GE = ME - KE = ME - $\frac{1}{2} m\,v^2$ , which agrees with option C

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Identify the layer of atmosphere in which we live.

topjm [15]

We are in the lowest layer called Troposphere.

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3 years ago

Tina is driving her sports car down US1, traveling 27m/s. She sees her friend Rita up ahead, waiting to cross the street at the

mrs_skeptik [129]

Answer:

434 Hz

Explanation:

According to the Doppler effect, when a source of a wave is moving towards an observer at rest, then the observer will observe an apparent frequency which is higher than the original frequency of the source.

In this situation, Tina is driving towards Rita. Tina is the source of the sound wave (the horn), while RIta is the observer. Since the original frequency of the sound is 400 Hz, Rita will hear a sound with a frequency higher than this value.

The only choice which is higher than 400 Hz is 434 Hz, so this is the frequency that Rita will hear.

3 0

3 years ago

Compare the energy consumption of two commonly used items in the household. Calculate the energy used by a 1.20 kW toaster oven,

9966 [12]

Answer:

The energy consumption by toaster oven is 432 kJ and that of fluorescent light (CFL) bulb is 435 kJ.

Explanation:

Power of toaster oven, P = 1.2 kW

Time, t = 6 minutes = 360 s

The energy used by toaster oven is given by :

$E=P\times t\\\\E=1.2\times 10^3\times 360\\\\E=432000\ J\\\\E=432\ kJ$

Power of fluorescent light (CFL) bulb, P' = 11 W

Time, t' = 11 h = 39600 s

Energy used by fluorescent light (CFL) bulb is given by :

$E'=P'\times t'\\\\E'=11\times 39600\\\\E'=435600\ J\\\\E'=435\ kJ$

So, the energy consumption by toaster oven is 432 kJ and that of fluorescent light (CFL) bulb is 435 kJ.

5 0

3 years ago

a spotted lizard runs at 3m/s at top speed. a girl wants to catch the lizard to keep as a pet. where should the girl place her c

Ann [662]

The acceleration due to earth's gravity is -9.8 m/s [dn] I thought... I'm assuming this is a projectile motion question asking for the range.

Break each kinematic quantity into their x and y components.

x y

v₁ = 3 m/s 0

v₂ = 3 m/s ?

Δd = ? -1.5

Δt = ? ?

a = 0 -10 m/s²

So the variable we are trying to find is Δdx (x component of displacement). We need to use a kinematic equation to do so. However, we obviously don't have enough given to find Δdx. This means we need to find something first, something we can use. How about Δt? Δt can be applied to both the x and y components. We have enough information in the y component list to find Δt. We can use this formula and solve for Δt.

Δdy = v₁y ( Δt ) + 1/2 ( ay ) ( Δt )²

Δdy = 1/2 ( ay ) ( Δt )² <- the first term cancels out since v₁y = 0.

2Δdy = ay ( Δt )²

2Δdy / ay = ( Δt )²

√ 2Δdy / ay = Δt

√ 2(-1.5 m/s) / -9.8 m/s² = Δt

√ -3.0 m/s / -9.8 m/s² = Δt

√ 0.306122449 s² = Δt

0.5532833352 s = Δt

Now, we can use this newly found quantity to solve for Δdx using the x component values using the appropriate kinematic equation.

Δdx = ( v₁x + v₂x / 2) ( Δt )

Δdx = ( ( 3.0 m/s + 3.0 m/s ) / 2 ) ( 0.5532833352 s )

Δdx = ( 6.0 m/s / 2 ) ( 0.5532833352 s )

Δdx = ( 3.0 m / s )( 0.5532833352 s )

Δdx = 1.659850006 m

Therefore, the girl should place her cage 1.7 m away from the platform to catch the lizard.

This solution assumes that the acceleration due to gravity is -10 m/s² [dn] and not -9.8 m/s² [dn]. If you need -9.8 m/s² [dn], then just substitute it into my solution. This was a pain to type lol

6 0

4 years ago

A child on a spinning playground ride is 0.36 m from the center of the ride. The centripetal force on the child is 19 N. What is

White raven [17]

Centripetal force is easily calculated as long as you know the mass, m, of the object; its distance, r, from the center; and the tangential velocity, v. This equation is based on the metric system; note that the centripetal force, f, is measured in Newtons.

F = mv^2 / r

19 N = m ( 0.54^2) / ( 0.36)

Solve for m

M = 23.5 kg

6 0

3 years ago

Can someone please help me​

Can someone please help me